Author information

¹Department of Public Health Sciences, Clemson University, Clemson, SC 29605, USA. Electronic address: mheo@clemson.edu.

²Department of Medicine, Albert Einstein College of Medicine/Montefiore Medical Center, 3330 Kossuth Avenue Bronx, NY 10467, USA.

³Department of Psychology, College of Behavioral, Social, and Health Sciences, Clemson University, Clemson, SC 29634, USA.

⁴Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E6546, Baltimore, MD 21205, USA.

⁵Department of Medicine, University of Washington, 325 9th Ave., Seattle, WA 98104, USA.

⁶College of Pharmacy, University of Rhode Island, Avedesian Hall, 7 Greenhouse Rd, Kingston, RI 02881, USA.

⁷Department of Medicine, University of California, San Francisco, 1001 Potrero Ave, San Francisco, CA 94110, USA.

⁸Department of Behavioral Medicine and Psychiatry, and Department of Medicine, Section of Infectious Diseases, West Virginia University School of Medicine, 930 Chestnut Ridge Road, Morgantown, WV 26505, USA.

⁹Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114, USA.

¹⁰Department of Internal Medicine, University of New Mexico Health Sciences Center, University of New Mexico MSC 10 5550, Albuquerque, NM 87131, USA.

¹¹School of Health Research, Clemson University, Clemson, SC 29605, USA; Department of Medicine, University of South Carolina School of Medicine, 876 W Faris Rd, Greenville, SC 29605, USA; Department of Medicine, Prisma Health, Greenville, SC 29605, USA. Electronic address: alain.litwin@prismahealth.org.

¹²Clemson/Prisma Health.

¹³Johns Hopkins.

¹⁴Massachusetts General Hospital/Harvard Medical School.

¹⁵Montefiore Medical Center/Albert Einstein College of Medicine.

¹⁶UMass Memorial Medical Center.

¹⁷University of California San Francisco.

¹⁸University of New Mexico Health Sciences Center.

¹⁹University of Rhode Island.

²⁰University of Washington.

²¹West Virginia University.

²²Centers for Disease Control.

²³Emocha.

²⁴Gilead Sciences.

²⁵Harm Reduction Coalition.

²⁶Health First.

²⁷Hepatitis C Mentor and Support Group.

²⁸Hepatitis/HIV Project Direct, Treatment Action Group.

²⁹Monogram.

³⁰Medication-Assisted Recovery Services.

³¹National AIDS Treatment Advocacy Project.

³²National Viral Hepatitis Roundtable.

³³NY Department of Health and Mental Hygiene.

³⁴NY Department of Department of Health.

³⁵Orasure.

³⁶Quest Diagnostics.

³⁷State Medicaid Director.

³⁸Task Force for Global Health.

³⁹The American Association for the Treatment of Opioid Dependence.

Abstract

Background: Direct-acting antivirals (DAA) are highly effective for treating hepatitis C virus (HCV) infection even among people who inject drugs (PWID). Yet, little is known about patients' adherence patterns and association with sustained virologic response (SVR) rates. We aimed to summarize various adherence patterns and determine their associations with SVR.

Methods: Electronic blister packs were used to measure daily adherence to once-a-day sofosbuvir/velpatasvir during the 12-week treatment period among active PWIDs. Blister pack data were available for 496 participants who initiated DAA, and had ascertained SVR status. Adherence was summarized in multiple patterns, such as total adherent days, consecutive missed days, and early discontinuations. Thresholds for adherence patterns associated with >90% SVR rates were also determined.

Results: The overall SVR rate was 92.7% with median 75% adherence rate. All adherence patterns indicating greater adherence were significantly associated with achieving SVR. Participant groups with 42/84 (50%) or more adherent days, or less than 26 consecutive missed days achieved >90% SVR rate. When adherence was stratified by <50% versus ≥50%, only among those with <50% adherence, greater total adherent days during 9-12 weeks, and no early discontinuation were significantly associated with higher SVR rate. Participants with first month discontinuation and ≥2 weeks of treatment interruption had low SVR rates, 25% and 85%, respectively. However, greater adherent days were significantly associated with SVR (aOR = 1.10 (1.04, 1.16), p<.001) even among participant with ≥14 consecutive missed days.

Conclusions: Although suboptimal adherence can still result high SVR rates among PWID population, encouraging patients to take as much medication as possible, with fewer than 2 weeks consecutive missed days, and without early discontinuation, was found to be important for achieving SVR.

Clinical trial number: NCT02824640.